WASHINGTON (CNN) -- The U.S. Army has reopened an investigation into the death of Army Ranger Spc. Pat Tillman in Afghanistan, based on its ongoing questions of the case as well as those raised by Tillman's family, an Army official said.

The move came last month.

Tillman, who gave up a contract with the Arizona Cardinals to become a Ranger, was killed in Afghanistan on April 22 in what initially was described as a Taliban ambush.

However, weeks later, the Army announced in a brief statement that Tillman had most likely been killed in friendly fire by soldiers who did not realize in the confusion of the battle that they were firing at other Americans.

According to the report, after his platoon was split up, Tillman and others in his group came under heavy friendly fire from rifles and a machine gun.

In a second article Monday, the Post reported the Army had offered "a distorted and incomplete narrative" in Tillman's death. The paper cited internal Army documents that "describe Tillman's death by fratricide after a chain of botched communications, a misguided order to divide his platoon over the objection of its leader and undisciplined firing by fellow Rangers."

Army officials said Tillman's mother, Mary, went to Sen. John McCain, R-Arizona, seeking details of the roles and missions of other soldiers and officers present during the attack.

She also wanted to know why the Army took several weeks to announce it was a friendly-fire incident and had other questions, including why her son's bloodied uniform was burned, the officials said.

McCain approached the Army in October seeking additional information.

An Army official said that several Rangers were disciplined after the incident.

According to the official, one member received administrative charges; four were rotated out of the Ranger unit back into regular Army infantry units, and two were reprimanded.

The official said he did not know why the actions were never announced by the Army at the time of the incident, but noted that due to privacy regulations, names and details of administrative discipline are not released.